Neuroprotection by Brazilian Green Propolis against In vitro and In vivo Ischemic Neuronal Damage

Neuroprotection by Brazilian Green Propolis against In vitro and In vivo Ischemic Neuronal Damage

Masamitsu Shimazawa,1 Satomi Chikamatsu,1 Nobutaka Morimoto,1,2 Satoshi Mishima,3 Hiroichi Nagai,2 and Hideaki Hara1*

1Department of Biofunctional Molecules, Gifu Pharmaceutical University, Gifu, Japan

2Department of Pharmacology, Gifu Pharmaceutical University, Gifu, Japan

3Research Center, API Co. Ltd, Gifu, Japan

*For reprints and all correspondence: Professor H. Hara, PhD, Department of Biofunctional Molecules, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu, 502-8585 Japan. Tel: +81-58-237-3931; Fax: +81-58-237-5979; E-mail: hidehara@gifu-pu.ac.jp

Received January 4, 2005; Accepted March 6, 2005.

Abstract

We examined whether Brazilian green propolis, a widely used folk medicine, has a neuroprotective function in vitro and/or in vivo. In vitro, propolis significantly inhibited neurotoxicity induced in neuronally differentiated PC12 cell cultures by either 24 h hydrogen peroxide (H2O2) exposure or 48 h serum deprivation. Regarding the possible underlying mechanism, propolis protected against oxidative stress (lipid peroxidation) in mouse forebrain homogenates and scavenged free radicals [induced by diphenyl-p-picrylhydrazyl (DPPH). In mice in vivo, propolis [30 or 100 mg/kg; intraperitoneally administered four times (at 2 days, 1 day and 60 min before, and at 4 h after induction of focal cerebral ischemia by permanent middle cerebral artery occlusion)] reduced brain infarction at 24 h after the occlusion. Thus, a propolis-induced inhibition of oxidative stress may be partly responsible for its neuroprotective function against in vitro cell death and in vivo focal cerebral ischemia.

Keywords: focal cerebral ischemia, free radical, lipid peroxidation, middle cerebral artery occlusion, PC12 cell culture